Anyone with a Graco 4ever car seat?? I need your help

My son is 11 months and we got this car seat 💺 at Christmas. I took the inserts out because I thought he was to big for them but now I’m concerned because his head keeps falling forward and squishing down. Not to mention he screams bloody murder when I put him in it but will go into his infant carrier just fine. Does this mean I need to put the inserts back in? Sorry if this seems like a stupid question I have looked all over trying to find answers or pictures of what it’s suppose to look like for his age and weight and all that and i cant seem to find much of anything. I’m a first time mom and can use all the help I can get I just want to make sure my son is safe in the car seat